<!DOCTYPE html>
<html>
  <head>
    <title>mfrac numalign</title>
  </head>
  <body>
    <div style="position: absolute;">
      <math xmlns="http://www.w3.org/1998/Math/MathML">
        <mfrac linethickness="0">
          <mpadded width="100px" lspace="50px">
            <mspace width="50px" height="20px" mathbackground="red"></mspace>
          </mpadded>
          <mspace width="100px" height="20px" mathbackground="red"></mspace>
        </mfrac>
      </math>
    </div>
  </body>
</html>
